Currently, assessments of anatomical features, and in particular the motion of the walls of the left ventricle of human hearts may be performed by the subjective valuation by humans of the motion of individual wall segments. That is, an ultrasound or echocardiogram video of a moving left ventricle may be recorded for later analysis and/or observed in real time. A clinician observes the video, divides the observed wall of the ventricle into segments, and evaluates the motion of each segment to produce a wall motion score. Because different clinicians may segment the wall of the left ventricle differently, and score the movement of the segments differently, there is a difficulty in accurately reproducing assessment scores by different people based on the same data.
Systems have been developed which assist clinicians in scoring wall movement. Such systems process the ultrasound video to identify portions of the video corresponding to a desired wall and then evaluate the motion of the identified wall. This may require human interaction, or may be done automatically. Some such systems automatically segment the wall and color code the wall segment according to the instantaneous motion of the segment. Other such systems calculate motion vectors, identifying motion velocity and direction, for respective points on the identified wall. A motion display is overlaid atop the ultrasound video display. The display includes a set of lines respectively corresponding to points on the identified wall. The length of the lines indicate the speed and the angle of the lines indicate the direction of the motion of the corresponding point. Such systems aid a clinician in producing a wall motion score, but subjective evaluation is still required.
Further systems have been developed to automatically generate a wall motion score. Such systems estimate the motion of segments of a left ventricle wall by comparing a maximum and a minimum displacement of the segment wall. A score for each segment is then calculated. However, the accuracy of calculating wall motion by displacement is less than that of calculating wall motion based on the motion velocity and direction of wall segments.
The inventors have advantageously recognized it is desirable to remove the subjective element in generating a wall motion score while maximizing the accuracy of such an assessment. This will result in more uniformity and reproducibility in wall motion scores and will increase the value of a series of such scores across a plurality of patients or over time relating to a single patient.